The country’s most senior police officer said five groups have a "significant international dimension" with tentacles spreading into Holland, Spain and the UK, countries which provide established routes for importing drugs into Ireland.

Irish gangs are also working with Russian gangs, particularly on cigarette and drugs smuggling.

"The presence of Russian organised crime groups operating in Spain is also influencing the activities of Irish criminals there," said Mr Callinan.

Gardai are working with international law enforcement agency Interpol to monitor these groups.

At the heart of each organised crime gang is a core of around six to 12 leaders who oversee middle managers, who in turn control low-level criminals who carry out the day-to-day activities, said the Garda Commissioner.

The majority of gangs are centred in Limerick, Cork, Galway, Sligo and Dublin - and there is a lot of interaction between them, including on joint enterprises such as drug importation.

While the overwhelming majority of the gangsters are involved almost exclusively in drug trafficking, they also engage in other activities like cash-in-transit robberies, firearms offences and "upper end" burglaries to fund major drug deals.

Speaking before an Oireachtas committee on justice about gangland crime, Mr Callinan told TDs and senators there was close co-operation between gangs in the Republic and Northern Ireland.

The cross-border links help them trade in weapons and drugs, as well as counterfeit cigarettes, fuel laundering and stolen goods.

Detectives have "serious concern" about a "friction and facilitation" relationship between crime gangs and dissident republicans, who have been taxing some drug dealers in recent years, Mr Callinan said.

They also remain worried about the continued increase in cannabis factories, or grow houses.

Mr Callinan said the operations provided a very quick turnaround in harvesting the drug, leading to a "conveyor belt of money" to organised crime gangs.

Eastern Europeans as well as Irish gangs are generally behind the ventures.

Mr Callinan also revealed there was no great decrease in the use of cocaine and heroin in recent years in Ireland.

The police chief told the committee that although members of his force would not be taking their foot off the pedal in the race against organised crime, the drugs trade was so lucrative that nobody was naive enough to think it would ever go away.

Since new laws were introduced in July 2009 to target organised crime, they have been used to carry out 179 arrests. Eight people have been charged under the legislation, two for directing organised crime and six for participating.

Mr Callinan also revealed drugs worth more than €90 million have been seized already this year.

Recoveries up to September alone had already eclipsed the entire haul for all of last year, which was valued at around €90 million.